1. Field of the Invention
The present invention relates to a tool head structure which is used to screw a regular screw or a damaged screw and further can directly drill a hole in the working surface.
2. Description of the Prior Art
Conventionally, when using the tool heads (such as: slot screwdrivers, cross screwdrivers or star screwdrivers) to screw various screws, it often causes the following problems:
1. The screw was often screwed in an embedded manner to obtain a smooth and nice looking working surface, but the corresponding embedding working procedure of the screw head is troublesome, the operator must replace the tool head with drill bit to machine an embedding recess, and then replace the tool head again to screw the screws, thus greatly increasing the cost.
2. The head portion of the screw is often damaged by a damaged screwdriver head, and the damaged head of the screw will cause the screw unable to continue the screwing operation, so the operator must remove the damaged screw as soon as possible, thus reducing the whole work efficiency.
3. During a general screwing operation, the unbalanced force applied by the operator and the poor contact angle between the screwing tool and the screw often cause the screw head to be damaged, or a slippage during operation causes the unexpected injuries, thus not only causing the screw unable to continue the screwing operation, but also causing the severe problem of injury.
In order to solve a part of the abovementioned problems, as shown in FIG. 1, the tool head 10 disclosed by U.S. Pat. No. 6,868,572 B1 is mounted with a drill cone 11 at the center thereof, and the protruding driving portion of the tool head 10 is formed with a blade 101. Moreover, four claw portions 12 are extended from one end of the drill cone 11, and on the front edge of each claw portion 12 is formed a cutting portion 121. By such arrangements, this conventional structure can perform both the drilling operation and the screw driving operation. The damaged screw can be removed by engaging the claw portions 12 of the drill cone 11 in the screwing recess of the screw. However, the abovementioned structure still has the following problems:
1. The end portion of the drill cone 11 is extended to form four claw portions 12, so there is not a key ridge line of a general drill, but the four angle points or four equally divided cross bevel edge. Hence, this drill cone 11 has a poor grasping ability, thus often skidding on the surface of the machining object during an electric drive operation.
2. The engagement of the claw portions 12 of the drill cone 11 with the screwing recess of the damaged screw makes the claw portions 12 grasp the inner of the screwing recess of the screw, but the four claw portion 12 with cutting portions 121 doesn't have the chisel point which is the most important during the drilling operation, so the hole drilling ability of this drill cone 11 is relatively poor.
3. The end portion of the drill cone 11 is extended to form four claw portions 12, and a special machining method is required to form the four cutting portions 121 of different directions and angles, hence the working procedure is complicated and the machining difficult is relatively high.
In order to solve the abovementioned relevant problems, based on the accumulative research technology and experience in the field of the screwdriver and the screw tool, from the angle of improving the effect of making a hole and simplifying the working procedure, the applicant of the present invention has developed a tool head structure for screwing the damaged screw.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.